1. Field of the Invention
This invention relates to an apparatus for conveying the material to be sewn automatically from one step of a sewing operation to another.
2. Description of the Prior Art
A known apparatus for conveying the material to be sewn from one step of a sewing operation to another is shown by way of example in FIG. 1. It includes a first support A having at its top a box B in which a motor C is mounted. The box B also contains a driving pulley connected to the output of the motor C. A second support D is spaced apart from the first support A and has at its top a plate E by which a driven pulley F is rotatably supported. An endless conveyor belt G extends between the driving pulley and the driven pulley F and is movable in a direction shown by arrows if the motor C is driven. The second support D is provided in an area in which a particular step of the sewing operation is carried out, and the first support A in a different area in which the immediately following step of the operation is performed. If the material H to be sewn is placed on the endless belt G by a person working at the second support D, its weight bears upon the belt G and produces therebetween a frictional force which enables the material H to move with the belt G from the second support D to the first support A without slipping. A sensor I is provided on the box B and the material H contacts the sensor I upon arriving at the first support A. As soon as the material H contacts the sensor I, the operation of the motor C is stopped and the movement of the belt G is, therefore, discontinued. As soon as the material H is removed from the belt G by a person working at the first support A, the sensor I returns to its original position and the motor C is, therefore, driven again to resume the movement of the belt G for conveying another material to be sewn.
The apparatus as hereinabove described is suitable for conveying a flexible and relatively light material, but is difficult to employ for conveying a stiff and heavy material, such as a thick sheet of cloth, artificial leather or a mat, which is difficult to place on, or suspend from, the belt. It is unusable if the material to be sewn is, for example, a sheet of a stiff and inflexible material.
The apparatus also has the disadvantage of having a fixed distance between the first and second supports A and D. If the distance is not suitable for the use of the apparatus between any two steps of the sewing operation, it is necessary to change the belt G to a different one, or cut off a portion of the belt or add to its length so that the two supports A and D may be positioned at an appropriate distance from each other.